Preliminary study established that rabbit corneal endothelial fluid pump survival is promoted by relatively low concentration of calf serum, provided 1MuM adenosine is present in addition to Balanced Salt Solution and glucose. It was further established that the active component to promote the survival has M.W. greater than 10,000 daltons. This research is aimed at (1) purifying the active factor by using ultrafiltration membranes and gel filtration columns; (2) establishing the dose-response curve of the purified factor, and (3) comparing the purified factor with other known growth factors. (4) Using the knowledge gained on the readily available calf serum, the presence of a similar factor in the aqueous humor will be studied. Finally, (5) experiments will be aimed at knowing whether the active factor has any cellular growth promoting property. The establishment of such purified factor will improve the present corneal preservation fluids and might shed light on the cause of corneal dystrophies.